SNMP community:
snmp-server community public RO
SNMP trap community ( trap-group ):
snmp-server host 192.168.0.224 version 2c proba_group
Enable traps, you want to receive form the device:
snmp-server trap link ietf
snmp-server enable traps snmp authentication linkdown linkup coldstart warmstart
snmp-server enable traps ospf state-change
snmp-server enable traps ospf errors
snmp-server enable traps ospf retransmit
snmp-server enable traps ospf lsa
snmp-server enable traps ospf cisco-specific state-change [...]